diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index 9d7e072..1c6249a 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -212,9 +212,12 @@
 	 * @return	string
 	 */
 	function escape_str($str)	
-	{	
+	{
+		// Access the CI object
+		$CI->get_instance();
+		
 		// Escape single quotes
-		return str_replace("'", "''", $this->CI->input->_remove_invisible_characters($str));
+		return str_replace("'", "''", $CI->input->_remove_invisible_characters($str));
 	}
 	
 	// --------------------------------------------------------------------